How to copy/paste a baked sound f-curve?
I would suggest you bake the sound into one distinct property, like the scale of an empty you add for that purpose, and use it to drive all places where you need the sound f-curve. This way there is no duplicated data, and if you have to edit or change the sound you won't have to copy a bunch of animations every time.

You can also search for "bake action" from the spacebar menu to make the baked action into normal keyframes, and copy them around, but the driving method is better in my opinion.